Bumps [httplib2](https://github.com/httplib2/httplib2) from 0.18.0 to 0.19.0. - [Release notes](https://github.com/httplib2/httplib2/releases) - [Changelog](https://github.com/httplib2/httplib2/blob/master/CHANGELOG) - [Commits](https://github.com/httplib2/httplib2/compare/v0.18.0...v0.19.0) Signed-off-by: dependabot[bot] <support@github.com>